220 4984 article Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?Daniel_Kr=FCgler?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: std::optional - move is conditionally nothrow, what about copy? Date: Tue, 11 Jun 2013 22:34:38 +0200 Lines: 48 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1370982879 28688 80.91.229.3 (11 Jun 2013 20:34:39 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 11 Jun 2013 20:34:39 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCT7RVFA4QORBX4T32GQKGQEEEKG25Q@isocpp.org Tue Jun 11 22:34:40 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ea0-f200.google.com ([209.85.215.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UmVH6-0001yt-48 for gclcip-std-proposals@m.gmane.org; Tue, 11 Jun 2013 22:34:40 +0200 Original-Received: by mail-ea0-f200.google.com with SMTP id g15sf6281108eak.7 for ; Tue, 11 Jun 2013 13:34:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type:content-transfer-encoding; bh=wa+6mLazw360SykjYOD1HunwcPGuJg+XWX4UmSy8mgw=; b=LJbWBZIdaqWNcVFh+lLFL0BijWd5/1LI3tFMCIQXYgNT1r84D7JQDzIKEY9l0zDmeD cZ2TNxjYbsViRQ84fFhMh/oeQiFirqj/kEglR5FdgHOQyaC5Ffi8BHOubkYJ3qZ6EZUo en5+eLBqTiT3o9xOl9dBW+AjVSDOQgiLaplXdDAJWyg5wWvEpN2iN7IXAD/vEc1xJn65 OHBuKUSz1ULvqh9oJhRYiY2136Fbmwo1uDlHbunOPRJjl7th5mpE8GEFDc6jh+cCOf3t y8SBmGqkBLUSYw9LVpfWXqr8VKNvq9q6ZO6V8cjeSyITdyKkGo+rjxdB48Pl5mJykSQL j6CA== X-Received: by 10.180.76.174 with SMTP id l14mr1961518wiw.5.1370982879468; Tue, 11 Jun 2013 13:34:39 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.80.6 with SMTP id n6ls760134wix.18.canary; Tue, 11 Jun 2013 13:34:38 -0700 (PDT) X-Received: by 10.194.84.205 with SMTP id b13mr9523763wjz.92.1370982878352; Tue, 11 Jun 2013 13:34:38 -0700 (PDT) Original-Received: from mail-wg0-x229.google.com (mail-wg0-x229.google.com [2a00:1450:400c:c00::229]) by mx.google.com with ESMTPS id ez4si5723359wic.42.2013.06.11.13.34.38 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 11 Jun 2013 13:34:38 -0700 (PDT) Received-SPF: pass (google.com: domain of daniel.kruegler@gmail.com designates 2a00:1450:400c:c00::229 as permitted sender) client-ip=2a00:1450:400c:c00::229; Original-Received: by mail-wg0-f41.google.com with SMTP id k13so4441557wgh.0 for ; Tue, 11 Jun 2013 13:34:38 -0700 (PDT) X-Received: by 10.180.184.101 with SMTP id et5mr2444668wic.45.1370982878282; Tue, 11 Jun 2013 13:34:38 -0700 (PDT) Original-Received: by 10.217.119.134 with HTTP; Tue, 11 Jun 2013 13:34:38 -0700 (PDT) In-Reply-To: X-Original-Sender: daniel.kruegler@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of daniel.kruegler@gmail.com designates 2a00:1450:400c:c00::229 as permitted sender) smtp.mail=daniel.kruegler@gmail.com; dkim=pass header.i=@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:4984 Archived-At: 2013/6/11 R=F3bert D=E1vid : > >> The rationale for the lack of this specification is that > > > Is it a lack of specification for noexcept or a specification of lack of > noexcept for the constructors (and all other functions, as mentioned in > n3279)? As I understand it's the second. The point to decide on was: How much should the library specify, especially since it just has introduced noexcept and a lot of work would presumably arise to apply such rules consistently. Also it was important to get a feeling upon the possible effect on compile-time, I think. Therefore a set of guideline rules was suggested to help deciding on noexcept. > N3279 suggest C compatibility functions to "may be marked unconditionally > noexcept.", and "No other function (than destructors, functions with wide > contract, move-constructors/-assignment ops) should use a conditional > noexcept specification", what might be too strict (for instance, for > optional). Is this because there was no better agreement of that time? I don't know what you mean by "better agreement". It was a set of guidelines suggested and it was very helpful at that time. noexcept was considered to be most important for good candidates for potentially no-throwing operations and it should be hopefully easily possible to express this condition (remember influence on compile-time). There is no reason not to to reconsider these rules in the future. I suggest to publish a paper - similar to N3279 - that explains the suggested extensions and the expected impact on the standard. - Daniel --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/?hl=3Den. .